Wang Jizhang, Zeng Hui, Duan Wenhui, Huang Huaqing
School of Physics, Peking University, Beijing 100871, China.
State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
Phys Rev Lett. 2023 Aug 4;131(5):056401. doi: 10.1103/PhysRevLett.131.056401.
The respective unique merit of antiferromagnets and two-dimensional (2D) materials in spintronic applications inspires us to exploit 2D antiferromagnetic spintronics. However, the detection of the Néel vector in 2D antiferromagnets remains a great challenge because the measured signals usually decrease significantly in the 2D limit. Here we propose that the Néel vector of 2D antiferromagnets can be efficiently detected by the intrinsic nonlinear Hall (INH) effect which exhibits unexpected significant signals. As a specific example, we show that the INH conductivity of the monolayer manganese chalcogenides MnX (X=S, Se, Te) can reach the order of nm·mA/V^{2}, which is orders of magnitude larger than experimental values of paradigmatic antiferromagnetic spintronic materials. The INH effect can be accurately controlled by shifting the chemical potential around the band edge, which is experimentally feasible via electric gating or charge doping. Moreover, we explicitly demonstrate its 2π-periodic dependence on the Néel vector orientation based on an effective k·p model. Our findings enable flexible design schemes and promising material platforms for spintronic memory device applications based on 2D antiferromagnets.
反铁磁体和二维（2D）材料在自旋电子学应用中的各自独特优势激发了我们对二维反铁磁自旋电子学的探索。然而，二维反铁磁体中奈尔矢量的检测仍然是一个巨大的挑战，因为在二维极限下测量信号通常会显著降低。在此，我们提出二维反铁磁体的奈尔矢量可以通过具有意外显著信号的本征非线性霍尔（INH）效应有效地检测到。作为一个具体例子，我们表明单层硫族锰化物MnX（X = S、Se、Te）的INH电导率可以达到nm·mA/V²量级，这比典型反铁磁自旋电子材料的实验值大几个数量级。通过在带边附近移动化学势可以精确控制INH效应，这在实验上通过电门控或电荷掺杂是可行的。此外，基于有效的k·p模型，我们明确证明了其对奈尔矢量取向的2π周期性依赖。我们的发现为基于二维反铁磁体的自旋电子存储器件应用提供了灵活的设计方案和有前景的材料平台。
